Travellers accused of "terrorising" residents on an estate next to their encampment could have vehicles and livestock seized.
A community protection notice served on the group expires on Tuesday.
If the travellers do not move from Northampton's Pineham Locks, they could be taken to court in an attempt to seize their assets.
Director of the Gypsy Council, Joseph P Jones, said there is a shortage of sites nationally.
The notice was introduced after complaints of stone throwing, fly-tipping and threatening behaviour.
Conservative borough councillor James Hill said: "Residents have been terrorised. Nobody should have to deal with that."
County council colleague Pinder Chauhan said there had been "a lot of anti-social behaviour".
"We've had packs of dogs running around, we've had the use of air rifles, we've had stones being thrown at members of the public," she said.
"There have been reports of knives. One resident was threatened and told 'snitches get stitches'."
Northampton Borough Council issued a notice last week giving the travellers 48 hours to leave.
When they did not, a Community Protection Notice was served.
This says if the travellers fail to leave the council will take the matter to magistrates' court in order to seize vehicles, animals, caravans and livestock.
A council spokesman said the travellers own some of the land, but nobody can occupy it as it is on a flood plain.
Northamptonshire Police has increased patrols in Pineham Locks.
On Twitter, chief constable Nick Adderley said he hated "the thought of anyone feeling afraid, not listened to or helpless".
Mr Jones said: "It seems the Tories are again trying to gain the criminalisation of unauthorised encampments.
"There is a big shortage of sites throughout the country and it's going to get even worse. They have not catered for the expansion of our population."
He said councils "complain about unauthorised sites" but fail to "provide transit, negotiated or permanent stopping places".